as the topic implies.. between both the values change completely .. why ?

 

In the desk top dyno engine simulation program the "simulation engine" uses seat to seat timing. If you enter .050" timing
the program estimates the seat to seat timing for you.

The difference in degrees duration of the two measureing points
in this program is 56 deg for hydraulics, 44 deg for solids and about 33deg for rollers.

the " intensity" increases as you progress throu the different choices Hyd, solid, roller.
this is explained in the intructions.

"seat to seat timing" is not nessessairily the same as "advertized duration" which is what you see in the camshaft catologs.
Different manufactures use different lift points to qualify their
advertized durations. Some don't specify a check point at all.

The actual seat to seat timing in a running engine or "running duration" will vary a lot by other conditions. (valve lash, rocker geometry, valve train deflection, hyd lifter leak-down being some factors)
that being said:
Comp cams defines their advertized durations as .006" tappet lift for hydraulics, either .015" or .020" tappet lift for solids and rollers.

Crane cams uses .004" or .0045" for hyd and .015",.018" and .020" for solids and rollers.

As you can see measureing the same cam using comp's method will give totally different numbers than if Crane's method is used.

The only common measuring method used by most all cam manufacturers is the .050" lift method.

The only true way to establish the begining and end of valve motion in a running engine is to actually measure and observe it in a running engine. There is soffisticated test equipment that will do this, but its beyond you and me.
SAE defines seat durtation as .007" valve lift off seat.

Desk top dyno is only as accurate as the info you give it.
use the published advertized durations with a grain of salt when comparing one manufactures cams to anothers.
The valve lash used will vary this up or down.

They are all limited by the same built in limitiations and laws of physics in any one engine design.
A modern high performance hyd cam from one manufaturer will in fact have more in common design wise than actual differnce to another manufacturers.
Some, would have you think they've reinvented the wheel.

Hope this has added much more to your confusion

 

so ive got my 'build-up' the values change from seat-seat compared to @50.

which one gives me the info I need?

i assume @50 tho the results vary by far between both

 

Use the .050" method to directly compare the .050" specs of a cam and the effect on power output compared to another cam. @.050"
Then use the Advertised durations published by the manufacters
for the cam(s) you want to compare.
Use a generous "grain of salt" when doing this as Advertrised duration is not the same as "running duration"
which is what the program actually needs to produce a good model.

Draw your own conclusions.

Desk top dyno is a neat learning tool.
But keep in mind it's a $39 program.